This invention relates to a chemical method of decreasing nitric oxide, NOx, levels, and more particularly to a composition of matter for reducing NO.sub.x levels in diesel fuels.
Nitrogen oxides are the oxidation products of elemental nitrogen, organic, or inorganic nitrogen and oxygen at elevated temperatures. Nitrogen oxides include nitric oxide, NO; nitrogen dioxide, NO.sub.2 ; nitrogen trioxide, NO.sub.3 ; dinitrogen trioxide, N.sub.2 O.sub.3 ; tetranitrogen pentaoxide, N.sub.4 O.sub.5 ; tetranitrogen hexaoxide, N.sub.4 O.sub.6 ; nitrous oxide, N.sub.2 O; and the like. Elevated temperatures required to prepare these oxidation products are routinely obtained in internal combustion engines utilizing gasoline, diesel, or aviation fuel.
There are very strong ecological and environmental reasons to reduce or ideally eliminate NOx as an internal combustion oxidation product. Once produced, NOx is directly responsible for acid rain and photochemical smog. Moreover, chronic exposure to NOx has been directly linked with restricted pulmonary compliance in non-smoking healthy males; acute respiratory disease among children living in "high exposure" towns in Czechoslovakia; and a key irritant cited for the high incidence of chronic bronchitis among Japanese postal workers servicing urban centers as outlined in Medical and Biologic Effects of Environmental Pollutants by the National Academy of Sciences, 1977.
Numerous physical methods have been suggested to reduce or eliminate NOx. Certain proposed techniques involve a great deal of capital outlay and require major consumption of additives, scrubbers, etc. For example, U.S. Pat. No. 3,894,141 proposes a reaction with liquid hydrocarbons; U.S. Pat. No. 4,405,587 proposes high temperature burning with a hydrocarbon; U.S. Pat. No. 4,448,899 proposes reacting with an iron chelate; U.S. Pat. No. 3,262,751 reacts NOx with a conjugated diolefin. U.S. Pat. No. 3,900,554 utilizes a combination of ammonia and oxygen to react with nitric oxide.
Application of these reactions discussed above imposes organic pollutant disposal problems along with the attendant problems of toxicity and malodorous environments. In addition, they require the presence of oxygen and are relatively expensive. And, all of these methods discussed must deal with the problem of the odor of ammonia and its disposal. Moreover, these methods also suffer from the drawback of requiring controlled environments which make them impossible to use in mobile vehicles.
Thus, an object of the present invention is to provide an economical means and/or a composition of matter that effectively reduces NO.sub.x in diesel fuels.